Checkout a new branch without any history

Extract file from another branch.

List only the root and merge commits.

Change previous two commits with an interactive rebase.

git rebase --interactive HEAD~2

List all branch is WIP

git checkout master && git branch --no-merged

Find guilty with binary search

git bisect start # Search start
git bisect bad # Set point to bad commit
git bisect good v2.6.13-rc2 # Set point to good commit|tag
git bisect bad # Say current state is bad
git bisect good # Say current state is good
git bisect reset # Finish search